US2122061A - Multiwall bag of paper or similar material - Google Patents

Description

June 28, 1938. oppg, 2,122,061

' MULTIWALL BAG OF PAPER .OR SIMILAR MATERIAL Filed Sept. 21', 1954 s Sheets-Sheet 1 TTEnLb a/ z b I (Z) L='-L r-:.

4 rfw l a mw Edgar Hoppe June I E HOPPE muunwm, age OF PAPER OR SIMILAR MATERIAL Filed Sept. 21, 1954. 3 Sheets-Shee't 2 gn/uxz/vviod- Edgar Hoppe Patented June 28, 1938 UNITED STATES PATENT OFFICE 2,122,061 MULTIWALL BAG OF PAPER OR SIMILAR MATERIAL Edgar Hoppe, Amsterdam,

to St. Regis Paper Company,

Netherlands, assignor New York, N. Y.,

In Germany 7 Claims.

to pasted end bags, but particularly to multl-ply bags of paper, or similar material, in which one or both ends are closed by arranging opposite plies in stepped formation and adhesively connecting these plies together.

Existing methods of forming such bags differ from each other mainly in the cutting of the ends of the separate bags. In case of one of the known methods the separate inside layers project 10 in a step-like manner over the outside layers, or

on the contrary, they are shorter than the outside layers also in a stepped order.

Another method of manufacturing bags, which in comparison to the above mentioned method represents a considerable improvement, provides longitudinal edges stepped on one side flap on the inside and on the opposite side flap on the outside. The folded end flaps of the individual tubes in this case are of equal length, i. e. they go are not stepped.

All known methods provide, however, that the steps at the bag ends, lying opposite ,to each other, are of equal width with respect to each other, so that when forming the bag bottom by folding the side flaps, the free part of each separate longitudinal edge is placed on the free part of the opposite longitudinal edge of the same tube and pasted together.

This separate interpasting, at least of the longitudinal edges of each individual tube, was heretofore considered absolutely necessary in order to obtain a secure and strong closure. Such method requires, however, precision and accuracy in regard to laying the individual layers one to the other before they are formed into tubes. However, it is a simple matter-for the paper layers to shift with reference to each other during the formation of the tubes, so that the steps do not register. 1

It has been found, however, that the pasting of each longitudinal edge individually with the opposite lonigtudinal edge of. the same tube is not so important in regard to the strength of the closure as it was considered previously, and that it is not essential to make the steps of the individual paper plies or individual tubes absolutely equal to one another in case that it is to be stepped at all. Furthermore, it has been found that deviation from the usual way of forming this kind of a bag even obtains a stronger pasting of the bag bottom.

It is possible, therefore, to give different widths to the opposite individual steps and achieve a considerable simplification of the manufacturing 5 process and at the same time to retain and even This invention relates April 21, 1934 increase the advantages offered by stepped bags generally.

For example, it is possible to lengthen the inside edge of a longitudinal step to such an extent that it partly or even completely covers the opposite step of the next layer. When folded in this manner two or more steps of the opposite side arecovered whereby eventually the next to the outside following edge does not need at all to cover the opposite edge of the corresponding layer or to be pasted with it.

It has been found advantageous to make two or more steps of the one longitudinal side equally long so that they cover one another completely and only the inner edges project over and are pasted to one or more of the opposite longitudinal edges. The above mentioned examples have only the purpose of showing that the width of the steps or the relation of the widths of the steps to I each other can be actually varied to a large extent without diminishing the advantages of the stepped bag. It will be understood that upon separating a bag length from the bag tube; the difference in the width of the steps always produces a corresponding formation of steps in reverse direction in the following bag length.

The strength of the bag closure produced by the above described method can be still increased by interpasting the.single tubes at their ends either throughout the whole or part of their circumference, thereby completely abandoning the principle of absolute independence of the longitudinal edges or that of the side flaps from each other, according to the old manufacturing methods.

This pasting may be accomplished before the bag tube is formed and is especially important if two steps completely overlap each other, i. e. one inner step extends up to or over the height of the following step. To suit the purpose the individual tubes preferably are pasted together in such case not only at the side flaps, but also at the end flaps. The last measure has proved especially important in case of bag closures with unstepped side flaps.

By pasting together the single paper webs before the formation of the tube, a further advantage is gained, namely that the individual paper webs remain secure in their relative position to one another. The above advantage makes the application of this measure especially advisable in case of bags, which are formed by tubes with equal sized steps.

By further developing the idea of pasting the individual paper webs together, the invention proiii) poses in case of steppe bags of the described kind, and mainly in case of bags provided with side flaps, which together with side flaps folded over t em are used on one side of the bag for the formation of the valve, to eliminate the fre quent trouble of the folded flaps fallingout rather short, if no special precaution is taken, and therefore exposed to the danger of being blown out of the bag when it is filled. This danger is eliminated according to the invention in such way that besides the pasting together of the flaps the back side of the flap which at folding forms the innermost flap, is pasted to the stepped side flaps insofar as it touches them. The strength of the valves is thus increased to a considerable extent.

In many cases it is desirable to lengthen the valve flap in order to secure a still more reliable In order to attain this.-

closure of the valve. it has been proposed to provide a special elongation of the valve flap, formed at the folding which is afterwards pasted in. The same result is attained according to the invention bythe manufacturing method described below in a much simpler and more advantageous manner and without additional consumption of material and waste by separation of single bag lengths from each tive tearing of the perforation.

To enable this kind of separation it is necessary to transfer those parts of the above mentioned pre-cut paper web, which are still unweakened until final cutting takes place, to the outer edges.

.It is advisable to transfer also the longitudinal glued seams of the tubes to the unstepped parts of the web. V

The lengthening of the valve is attained in such way that the outer parts of the tube forming the flaps are cut on the one side of the bag tube at a difierent level from the other side or from the middle level of the steps, and in such way that the flaps on the side provided for the formation of the valve are longer than on the other side. This means that the corresponding out is displaced with reference to the level of the other and results in a corresponding shortening of the adjoining flap in the following bag length. This is, however. of no disadvantage, since the valve is formed anyway only on one side of the bag and for the formation of a simple bag closure without a valve shortened flaps are sufllcient, especially if besides the usual pasting they are pasted like the valve flaps also along their inner sides with the longitudinal edges.

The cut separating the valve flap from the iongitudinal edges is made deeper than the level of the shortest step of the longitudinal flaps, which enables lengthening of the valve flap at least up to the heightofthe longest step. The surface of contact between the longitudinal edge and the valve flap is thereby substantiallyv enlarged and the safety of-the valve closure, especially when pasting these parts in the aforemen tioned manner, considerably increased.

The final result is that by these means considarable lengthening of the valve flap is attained which allows a proper valve formation in the case of wholly or partly interpasted edges of the individual paper webs. The application of the above described idea is, however, not restricted only to the bass with stepped longitudinal edgesand unstepped side flaps, but also is applicable to such bags, which are not stepped at all, i. e. the individual tubes of which are cut in their whole circumference equally and only the side flaps are separated from the part forming the longitudinal edges by cuts and on the other hand also to bags stepped all round as well as to singleply bags of the annexed drawings which illustrate for example some of the described bag forms and which are comprehensible without further explanation.

Fig. 1a is a plan view showing an unfolded closure forming part of the bag having stepped side flaps, the steps of which are unsymmetrical on opposite sides being separated from the folded end flaps by a longitudinal cut.

' Figure 1b is a view similar to Fig. 1a showing one side flap folded along the line g-h.

Figure 2a is a plan view of a bag end similar -to that shown in Fig. 10., but having the flap elongated on the side forming a valve flap.

- Figure 2b is a plan view of a bag end similar to Fig. 2a except that the plies are not stepped.

Figs. fia'ancl 3b are plan views of a portion of a bag tube length showing the cutting lines for effecting the valve flap shown in Figs. 2a and 2b.

Fig. 4 shows the shape of the ends of the unfolded individual tubes of a three wall bag with an elongate valve flap.

In the forms of the invention shown on the drawings, it is of no importance whether thebag is provided with gussets or not, or whether it is an open mouth bag or a valve bag, with the exception of such improvements, which refer to the valve or its formation. v

The Figures la. and 1b demonstrate the different widths of the opposed sets of helps I, 2, 3 of a three-wall bag'tube, and the overlapping of iongitudinal edges, after the side flaps 4 and 5, which latter are of equal width, have been folded inwardly.

In the upper part of Fig. la the visible steps of the longitudinal edges i, 2 and 3, and in the lower part of the figure the invisible steps outlined with dashed lines and marked with figures in parentheses are shown; also steps (2) and (8). covered by the innermost longest step (i). After folding the lower side flap inwardly along the folding being disposed below and the steps (2) and (3) being disposed over the step i). If the side flap shown in the upper part of the figure is folded inwardly along the line (i-Jc), it is clear that the wider step (i) comes to lie over the steps i and 2 of the opposite side and even partly covers the step (3). In order to show the separation lines the lines of the single steps are marked a-b,

0-42 and e-f, the lines resulting after folding the steps are marked (it-4i), (c-d) and (6-4).

The Figures 2a and 2b are comprehensible line (g-h), the several longitudinal edges of the 1 plies are rendered visible, the innermost-step i) v a bag bottom of an entirely unstepped bag shown on Figure 21),, only the upper layer of the unfolded closure, 1. e. the inner layer of the side flaps is visible.

In the unseparated bagtube shown on Figs. 3a and 3b, the separating lines are indicated by the reference numerals 6, I and 8. 9 are cutting lines lying in the middle level, near the outer edge on the side not intended for valve formation, and III are cutting lines shifted from the middle level on the side intended forvalve formation, both lines extending longitudinally of the bag tube. It will be seen that the cutting lines ll extending longitudinally of the bag tube and separating the end flaps from the side flaps extend up to the level of the shortest step.

Fig. 4 shows the cutting of the ends of the unfolded individual tubes of a three-wall bag, the steps of the side flaps being marked I, 2 and l. The valve flap is indicated at 5, only one layer being seen. On this flap are marked with dotted lines the planes 12, which come to lie againstthe side flaps and are pasted to them when the valve flap is folded. The glued longitudinal seams ll, 14 and I5 lie as described above in the unstepped part of the bag, i. e., these seams terminate in the end flaps as distinguished from side flaps.

Of course, the invention is not restricted to the above described or to the fund bags illustrated in the drawings, but can be changed in various respects without departing from the spirit of the invention, especially as claims.

What is claimed:

1. A multi-ply bag having an end closure consisting of side flaps and end flaps, said side flaps being materially more extensive than the end flaps and having their longitudinal edges arranged in stepped relation on opposite sides, a step on one side substantially throughout its length overlapping more than one step on the otherside at the ends of said edges, and the undersurface of each step of one side flap engaging one or another step of the opposite side flap, and means to secure the side flaps together.

2. A multi-ply bag having an end closure consisting of side flapsand end flaps, said side naps having their longitudinal edges arranged in stepped relation on opposite sides, the lengths of the corresponding steps transversely of the bag on the opposed side flaps being different, and means for securing the side flaps together.

3. Multi-ply satchel bottom bag having the piles formed from sheets united by longitudinal addefined in the app hered seams, said seams all terminating in end flaps as distinguished from side flaps, and a valve in the end of said. bag opposed to said seams.

4. A multi-ply bag having an end closure consisting of side flaps and end flaps separated by cuts running longitudinally of the bag, said side flaps having their longitudinal edges arranged in stepped relation on opposite sides, the lengths of the corresponding steps transversely of the bag on the opposed side flaps being different, the end flap on one end being longer than the other end flap, the longer end flap, being inside of and free from adjacent flaps for securing the side flaps together.

5. A multi-ply bag having an end closure consisting of side flaps and end flaps separated by cuts running longitudinally of the bag, said side flaps having their longitudinal edges arranged in stepped relation on opposite sides, a step on one side overlapping more than one step on the other side, the lengths of the corresponding steps on opposed side. naps being diiferent, and means for securing the side flaps together.

6. A multi-ply bag having an end closure consisting of side flaps and end flaps separated by cuts running longitudinally of the bag, said side flaps being materially more extensive than the end flaps and having their longitudinal edges arranged in stepped relation on opposite sides, the step on one side substantially throughout its length overlapping more than one step on the other side at the ends of said edges, and the under surface of each step of one side flap engaging one or another step of the opposite side flap, the end flap on one end being longer than the other end flap, the longer end flap being inside of and free from adjacent flaps to form a valve, and means to secure the side flaps together.

7. A multi-ply bag having the plies formed from sheets united by longitudinally adhered seams, an end closure consisting of side flaps and end flaps, said seams all terminating in said end flaps, said side flaps having their longitudinal edges arranged in stepped relation on opposite sides, the lengths of the corresponding steps transversely of the bag on the opposed side flaps being diilerent, and means to secure the side flaps together.

. EDGAR HOPPE.

to form a valve, and means

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